Device for forming a selvedge on a fabric

ABSTRACT

Device for forming a selvedge on a fabric comprising at least one thread guiding element ( 8 - 9 ) for what is called a leno thread ( 10 - 11 ), provided on an arm ( 16 ), whereby this thread guiding element ( 8 - 9 ) can be moved by means of a drive mechanism ( 24 ), characterised in that the drive mechanism ( 24 ) comprises the combination of an oscillating drive element ( 25 ); coupling parts ( 26 ), and a mechanism ( 27 ) with which the movement of one of the above-mentioned coupling parts ( 26 ) can be translated in a lateral movement of the above-mentioned thread guide ( 17 - 18 ).

The present invention concerns a device for forming a selvedge on a fabric, in other words a device which is designed to be used in weaving machines in order to provide for a selvedge during the weaving process.

Selvedge weaves, as well as devices for forming a selvedge, are known as such from the state of the art and are described among others in EP 0,286,619 and WO 96/36751.

Since the principle of forming such selvedge weaves, for which what are called leno threads and what is called a fixed thread are generally used, is generally known, these weaves as such will not be further discussed here.

As far as the known devices are concerned, it should be noted that they have several disadvantages. Thus, for example, they usually have continuously rotating parts, in particular rotating cams, gear wheels or the like, of which it is known that they attract and accumulate the dust which is present in weaving rooms. Also, such devices have to be cleaned on a rather regular basis. Even when they are regularly cleaned, the risk of fluffs coming off and adhering themselves to the fabric is large.

The present invention aims a device for forming a selvedge with a simple construction and requiring little maintenance, whereby the above-mentioned disadvantages are minimised.

To this end, the invention concerns a device for forming a selvedge on a fabric comprising at least one thread guiding element for what is called a leno thread, provided on an arm, whereby this thread guiding element is provided with a thread guide and whereby at least this thread guiding element can be moved by means of a drive mechanism, such that its position can be laterally changed on the one hand, and can be changed in height on the other hand, characterised in that the above-mentioned drive mechanism comprises the combination of an oscillating drive element; coupling parts forming a connection between the drive element and the above-mentioned arm in order to move said thread guide in height; and a mechanism with which the movement of one of the above-mentioned coupling parts can be translated in a lateral movement of the above-mentioned thread guide in order to laterally change its position.

The device is preferably also provided with at least one thread guiding element for what is called a fixed thread, provided on an arm, which then forms a shed together with at least one so-called leno thread.

By a ‘lateral change of the position of the thread guide’ should be understood among others that in the case where a thread guide for what is called a fixed thread is being applied as well, which is usually the case, the thread guide for a leno thread is situated in one position along one side of the thread guide for the fixed thread, whereas it will be situated on the other side thereof after a switching. By a ‘change in height’ is meant the altered position which is necessary for forming the shed.

As use is made according to the invention of an oscillating drive element on the one hand and coupling parts on the other hand consisting of parts moving to and fro, the usual rotating parts and the ensuing disadvantages, such as the formation of dust accumulation and the like, are excluded or at least minimised. Moreover such a device, which does not contain any continuously rotating cams or gear wheels between the drive element and the thread guides, requires very little maintenance.

The oscillating drive element preferably consists of a motor, in particular a stepping motor, with a motor shaft which is driven back and forth.

The invention is particularly useful in embodiments with at least two arms whereby these arms and/or the accompanying thread guiding elements can be moved crosswise in surfaces situated next to each other.

The threads concerned preferably extend directly backwards as of the thread guides, along the thread guiding elements, as is also the case in the embodiment known from WO 96/36751, and one or several of the above-mentioned thread guides are embodied as a thread guiding eye situated in a surface which extends crosswise to the surface in which the thread guiding element concerned can be moved in height. As the threads are guided off directly to the back on the one hand, and moreover thread guiding eyes are used on the other hand situated in a surface crosswise to the surface in which the thread guiding element concerned can be moved in height, this offers the advantage that the threads are bent only very little and thus are also little subject to wear, as a result of which the risk of thread breaks is considerably reduced.

This advantage can also be obtained in other devices, for example also by using such thread eyes in combination with the embodiment described in WO b 96/36751. That is why the invention, according to a second aspect, also concerns a device for forming a selvedge on a fabric comprising several thread guiding elements, including for example at least one thread guiding element for what is called a leno thread and at least one thread guiding element for what is called a fixed thread, whereby these thread guiding elements are embodied as protruding elements, in particular needle-shaped elements, provided with a thread guide at least on their front ends, whereby the threads concerned extend mainly according to the longitudinal direction of the thread guiding elements and/or extend mainly along these thread guiding elements, and whereby these thread guiding elements can be moved in height by means of a drive mechanism, characterised in that the above-mentioned thread guides are formed as thread guiding eyes situated in surfaces situated crosswise to the surface in which the thread guiding element concerned can be moved in height.

Further preferred embodiments will appear from the following description and accompanying claims.

In order to better explain the characteristics of the invention, the following preferred embodiments are described as an example only without being limitative in any way, with reference to the accompanying drawings, in which:

FIG. 1 represents a device according to the invention in perspective;

FIG. 2 is a side view of the device from FIG. 1;

FIG. 3 is a strongly schematic section according to line III-III in FIG. 2;

FIG. 4 represents a section to a larger scale according to line IV-IV in FIG. 2;

FIGS. 5 and 6 represent views analogous to that in FIG. 4, but for two other positions;

FIG. 7 represents a section according to line VII-VII in FIG. 5;

FIGS. 8 to 17 concern different positions of the device, whereby the FIGS. 11, 13 and 17 each represent highly schematic sections, according to lines XI-XI in FIG. 10, XIII-XIII in FIG. 12 and XVII-XVII in FIG. 16 respectively;

FIG. 18 represents a view similar to that according to arrow F18 in FIG. 16, but for a variant;

FIGS. 19, 20 and 21 represent a variant of the invention, in three different positions;

FIG. 22 represents a part of the device from FIGS. 19, 20 and 21 in perspective;

FIGS. 23, 24 and 25 represent a side view of the part from FIG. 22, for the positions of FIGS. 19, 20 and 21 respectively;

FIG. 26 represents another view according to arrow F26 in FIG. 23;

FIG. 27 represents a special embodiment of a thread eye which can be applied in a thread guiding element of a device according to the invention;

FIG. 28 represents a section according to line XXVIII-XXVIII in FIG. 27;

FIGS. 29, 30 and 31 represent a variant of FIG. 27.

The figures represent a device 1 according to the invention which is suitable to form two selvedges 2 on fabric parts 3 formed next to each other. Also, this device 1 is made doublefold and comprises two groups of thread guiding elements whereby every group, 4-5 respectively, in this case comprises one thread guiding element 6 for what is called a fixed thread 7 and two thread guiding elements 8-9 for what are called leno threads 10-11.

The thread guiding elements 6 are provided on a rotatable arm 12 and are provided with thread guides 13 at their front ends. The thread guides 13 can only be moved in height, in particular in planes 14-15, as indicated in FIG. 3.

The thread guiding elements 8-9 are provided on a rotatable arm 16 and they are provided with thread guides 17-18 at their front ends. Every pair of thread guiding elements 8-9 is fixed on a base 19 which can be rotated, practically over 180°, as a result of which the thread guides 17-18 cannot only be moved in height, but also their mutual position can be altered.

As is known, every thread guiding element 6 can hereby move through the corresponding thread guiding elements 17-18, such that a rotation of the bases 19 will also have for a result that, in one position, the thread guide 17 is situated to the left and the thread guide 18 is situated to the right of the accompanying thread guide 13, whereas in the other position of such a base 19, this is exactly the opposite.

The arms 12 and 16 are made as lever arms which are fixed in a rotating manner to a frame 22 by means of rotating points 20-21. These arms 12, 16 are mutually coupled, in this case by means of a coupling bar 23, such that the movement of the arm 16 results in an opposite movement of the arm 12.

The device 1 is provided with a drive mechanism 24 which is mainly composed of an oscillating drive element 25; coupling parts, generically indicated with reference 26, which form a connection between the drive element 25 and at least one of the above-mentioned arms, in this case the arm 16, whereby these coupling parts preferably exclusively consist of parts moving to and fro, and which thus do not rotate continuously further; and a mechanism 27 with which the movement of one of the above-mentioned moving parts can be translated in a mutual lateral shift of the thread guides 17-18 in relation to the thread guide 13.

In the example, the oscillating drive element 25 consists of a motor 28 with a motor shaft 29 which can be driven to and fro. More in particular, a stepping motor is preferably used to this end.

In the given example, the above-mentioned coupling parts 26 are for example composed of a crank 30 mounted fixed on the motor shaft 29 and which thus can be rotated to and fro by means of the motor 28 on the one hand, and of a connecting arm 31 provided between the crank 30 and the arm 16, which is connected to the crank 30 and the arm 16 via hinge points 32-33.

The above-mentioned mechanism 27 comprises a tilting body 34 which is mounted on the arm 16 in a rotating manner via a shaft 35, as well as a cam following mechanism 36 with which the tilting body 34 can be moved. The cam following mechanism 36 consists of a cam follower 37 mounted fixed on the tilting body 34 on the one hand, and of a cam guide 38 provided on one far end of the connecting arm 31 on the other hand, in particular on the far end situated opposite to the hinge point 32 in relation to the hinge point 33.

Moreover, as represented in FIGS. 4 to 7, the tilting body 34 is connected to the bases 19 in such a manner that a tilting movement of the body 34 results in a rotation of the bases 19 over practically 180°. To this end, these bases 19 are mounted fixed on shafts 39. On these shafts 39 are provided cranks 40 which mesh in a hinged manner via shafts 41 in carriages 42 sliding in guides 43 in the tilting body 34.

The oscillating drive element 25 is preferably coupled to a non-represented control which makes it possible for the motor shaft 29 to rotate between at least three positions, a first position in which the crank 30 is situated in a position as represented in FIG. 2 on the one hand, and a second and third position whereby the crank 30 is turned over a certain angle A to the one direction, over a certain angle B to the other direction respectively on the other hand. In the given example, these angles A and B amount to 1200.

Further, the cam guide 38 is positioned and embodied such that the cam follower 37, as the drive element, i.e. the crank 30, is shifted as mentioned above from the first into the second position, makes contact with a cam guiding part N1 which leaves the lateral position of the cam follower 37 unaltered or practically unaltered, and such that the cam follower 37, as the crank 30 is shifted from the first into the third position, makes contact with a cam guiding part N2 which causes a lateral movement Z of the cam follower 37 and thus brings about a rotation of the bases 19.

It is clear that, according to the invention, this can also be realised in another manner than by means of a cam guide.

The working of the device 1 is described hereafter by means of the successive figures and the different positions represented therein.

FIGS. 1 to 3 represent a condition whereby the crank 30 is situated in the first position. By realising the coupling parts 26 in a fitting manner is thus obtained that the thread guiding elements 6 on the one hand and the thread guiding elements 8-9 on the other hand, seen from a side view, are situated away from each other.

For the above-mentioned first position, the tilting body 34 is situated in a position as represented in FIG. 4.

When the crank 30 is brought in the second position, in other words is rotated over the aforesaid angle A, a condition is first obtained as represented in FIG. 8 to finally obtain a condition as represented in FIGS. 9 to 11. It is clear that this condition is the result of the mutual coupling of all parts.

It should be noted that during this movement, the point of application of the cam follower 37 in the cam guide 38 hardly changes, thanks to a suitable configuration between the different parts. Thus, the cam follower 37 will hereby stay present in the cam guiding part N1, as a result of which the tilting body 34 remains in the position of FIG. 4 and the bases 19 consequently will not be rotated.

It is clear that, when the crank 30 is turned back over the angle A, there will be a movement in the opposite direction.

When the crank 30 is brought into the third position, in other words is rotated over the aforesaid angle B, there will first be an intermediate position, as represented in FIG. 12, whereby the cam follower 37 is moved along the slanting part of the cam guide 38, as represented in FIG. 5. As a result, the body 34 will tilt from the position represented in FIG. 4, over the position from FIG. 5, into the position from FIG. 6. Consequently, the cranks 40, and thus also the bases 19, will make a rotational movement of about 180°, as is schematically represented in FIG. 13.

This rotation is entirely or almost entirely completed, before the thread guiding elements 6 on the one hand and the thread guiding elements 8-9 on the other hand start to cross each other, i.e. before the situation of FIG. 14 is created.

Following the situation of FIG. 14, the arms 12 and 16 will further move into the situation as represented in FIGS. 15 and 16.

As the crank 30 is turned back over the angle B, the following movements take place in the opposite direction.

It is clear that by shifting the crank 30 to and fro either exclusively over the angle A, or exclusively over the angle B, or for example alternately over the angle A and the angle B, different selvedge weaves can be realised by means of the threads 7 and 10-11.

By controlling the crank 30 can thus be realised a selection of different selvedge weaves.

It is clear that the device 1 can also be made simple, i.e. for forming a single selvedge weave. Nor is it excluded to work with only one thread guide 17 or 18 on a base 19, whereby only one leno thread is used then, which, as the crank 30 is turned over the angle B, will then be alternately situated on either side of the thread guiding element 6, seen from aside.

The threads 7 and 10-11 are preferably guided off directly to the back as of the thread guides 13 and 17-18, for example via thread guides 44-45 situated at the back on the arms 12 and 16. This offers the advantage that the threads 7 and 10-11 will be little subject to bends and that the length of the path followed by said threads is little variable during all the movements made. This effect can even be further improved by using thread guides, as represented in FIG. 18, which are made as a thread guiding eye situated in a surface situated crosswise to the surface in which the thread guiding element concerned can be moved in height. In FIG. 18, this is exclusively represented for the thread guide 13, but it is clear that a similar embodiment is preferably applied to the thread guides 17 and 18 as well. To this end, the thread concerned no longer has to move in an S-shape through the thread eye, as a result of which the threads will have less friction and the risk of thread breaks is minimised.

It is clear that different variants are possible. Thus, for example, instead of a locally provided motor 28, use can also be made of a drive element in the shape of an oscillating shaft which is driven for example in an oscillating manner via a coupling with another machine part.

Nor must the aforesaid crank 30 be provided directly on the motor shaft 29, and a reduction can be provided in between. Such a reduction can be easily built in in the motor housing or in a separate, sealed housing.

The cam guide 38 can be exchangeable, as a result of which different effects can possibly be created. Said cam guide 38 is also preferably open on the far ends, such that possible dust gathered therein can leave via the open ends and will not be accumulated.

According to a variant, the thread guiding element 6 is driven by its own drive mechanism, and thus separately from the drive mechanism 24 for the thread guiding elements 7-8. The thread guiding element 6 can be mounted on an arm 12 in a manner analogous to that of the given embodiments, or for example on a supporting element which can be moved up and down, such as a harness.

It is clear that, according to a variant, only one of the thread guiding elements 8 or 9 can be provided, which can be laterally moved by means of a device according to the invention. According to yet another variant, apart from the aforesaid thread guiding element 8 or 9, a thread guiding element can also be arranged centrally in the extension of a shaft 39, and thus provided such that it cannot be laterally moved on the arm 16. Naturally, such a thread guiding element should be arranged out of reach of an aforesaid thread guiding element 6, which thread guiding element 6 can then be moved for example with a harness.

The device 1 makes it possible to carry out a four-stroke movement as well as a two-stroke movement.

FIGS. 19 to 26 represent a variant of the invention whereby FIGS. 19 to 21 represent the entire device 1 in different positions, whereas FIGS. 22 to 26 represent certain parts of the device 1, seen in different positions as well as different views.

A first point of difference with the embodiment from FIGS. 1 to 17 consists in that the aforesaid mechanism 27 has been built in another manner.

The thread guiding elements 8-9 are provided in a manner analogous to that of the preceding embodiment, on a rotating base 19, whereby every thread guiding element 8, 9 respectively, is situated eccentrically as such in relation to the shaft 39.

The mechanism 27 now comprises a crank-shaped part 46 which is connected to the above-mentioned shaft 39 in a fixed manner and thus forms a laterally protruding part, whereby this crank-shaped part 46 is connected to one of the above-mentioned coupling parts 26 by means of a connecting rod 47, in this case the connecting arm 31.

In particular, the connecting rod 47 is coupled to the coupling part 26 concerned, i.e. the connecting arm 31, via a first hinge point 48, on the one hand, and it is connected to the aforesaid crank-shaped part 46 via a second hinge point 49 on the other hand, whereby these hinge points 48-49 have rotary shafts 50-51 which extend mutually in different directions and which are provided at a slanting angle on the sides 52-53 of the connecting arm 31 and the crank-shaped part 46 respectively, in particular such that what is called a Bennet four-bar mechanism is hereby formed.

It should be noted that the rotary shafts 50-51 are hereby situated at angles K1 and K2 in relation to a perpendicular on the sides 52, 53 respectively, which angles, as indicated in FIGS. 25 and 26, are equal. Also the distances L1 and L2 indicated in FIGS. 25 and 26 are equal.

The advantage of such a Bennett four-bar mechanism consists in that, at the height of the rotary shafts 50-51, formed of shaft ends, simple rolling bearings such as ball bearings, needle bearings or cylinder bearings can be applied, which, as is known, are little subject to wear.

It is clear that in the case of a double embodiment, with two rotatable bases 19, both bases 19 can be mutually coupled, such that the rotation imposed on one base 19 via the Bennett four-rod mechanisms will automatically be transferred to the other base 19. This can for example be done via a connection between the given crank 46A and a similar crank on the second base which is not represented. Naturally, also two Bennett four-rod mechanisms can be provided which are arranged next to each other.

It should be noted that, in the embodiment from FIG. 19, the thread guiding elements 8 and 9 are arranged in a plane which is almost perpendicular to the motor shaft 29. In case of a shift from the position in FIG. 19 to the position in FIG. 20, as well as in case of a shift from the position in FIG. 19 to the position in FIG. 21, there will be a respective lateral movement of the thread guiding elements 8 and 9.

A second point of difference consists in that the thread guiding elements, in FIGS. 19 to 21, the thread guiding element 6 as well as the thread guiding elements 8-9, are provided on arms 12-16 which can rotate around points of rotation 20-21 situated in or near the central plane 54 of the weaving surface 55, and in that the bisector of the angle described by such a thread guiding element 6, 8-9 respectively, deviates hardly or not from the above-mentioned central plane 54. In particular, the points of rotation 20-21 are preferably situated at distances L3-L4 from the central plane 54 which are smaller than 2 cm, and in that the bisectors concerned, if they deviate from the above-mentioned central plane 54, form an angle with the plane 54, which is smaller than 15 degrees.

Such a situation of the points of rotation 20-21 and the bisector offers the advantage that the length over which the threads 7, 10 and 11 are pushed through the thread guides 13, 17 and 18 as the arms 12-16 are turned, is restricted to a minimum, so that the risk of a thread break due to wear is minimised. It is clear that, although this principle can only be applied to one arm, it will preferably be applied to both arms 12-16, however.

Naturally, this can also be applied in other embodiments of the invention, for example in those of FIGS. 1 to 17. Finally, a special embodiment of a thread guide 13 is represented in FIGS. 27 and 28, which of course can also be applied to the thread guides 17 and 18. This thread guide 13 consists of a thread eye 56 provided at the free end of the thread guiding element concerned, formed of a passage 57 extending as of the crosscut end 58 of the thread guiding element, slantingly backwards, to thereby open into the side wall 59 of the thread guiding element. The passage 57 hereby preferably consists of a bore hole or the like. Thus is created a sort of ring at the top of the thread guiding element which thus functions as a thread eye. The advantage of this embodiment consists in that the thread guided through it is hardly or not bent, as is also the case in FIG. 18, but that the top must hot be widened and/or bent thereby either.

In principle, the embodiment from FIGS. 17 and 18 can also be realised by making use of a tubular thread guiding element with a front open end and an opening in the side wall, but the embodiment from FIGS. 27 and 28 is preferred, as dust accumulations easily occur in embodiments made on the basis of a tubular thread guiding element.

According to another variant, a wear-resistant thread guiding element can be provided at the far end of every thread guiding element concerned, in particular at the thread eye 56, for example in the shape of a ceramic cylindrical piece and/or insert piece, provided in the thread eye 56 or in the extension of the tubular part formed by the passage 57.

The embodiments of FIGS. 29 to 31 show other variants of a thread guide 13 whereby the thread eye 60 is formed of a bent wire. The use of a bent wire offers the advantage that the bending of the thread 7 with respect to the thread eye 60 is more smoothly around the outer surface of the wire. Such a wire can have a circular, an oval or another rounded cross section. Such a thread guide can be formed quite cheaply because only a wire has to be bent. As can be seen in FIG. 29 the thread eye 60 can be arranged perpendicular to the length direction of the thread guide 13. In FIG. 30 the thread eye 60 is arranged parallel to the length direction of the thread guide 13, while in FIG. 31 the thread eye 60 is arranged at an angle with respect to the length direction thread guide 13. In order to limit the bending of the threads guided in the thread eyes 60 of the thread guides 13, the embodiments of FIGS. 29 and 31 used in a device according to the invention seem preferable. Similarly, the other thread guides 17 and 18 can comprise such a bent wire in order to guide the leno threads 10 and 11. Such rounded thread eyes 60 are especially suitable for weaving threads consisting of glass fibres, because such threads easily break when guided along an edge and will normally not break when guided around a rounded surface.

The invention is by no means limited to the above-described embodiments given as an example and represented in the accompanying drawings; on the contrary, such a device for forming a selvedge can be made in different shapes and dimensions while still remaining within the scope of the invention. 

1-25. (canceled)
 26. Device for forming a selvedge on a fabric comprising at least one thread guiding element for a leno thread carried by an arm, said at least one thread guiding element being provided with a thread guide and wherein at least said at least one thread guiding element is moveable by a drive mechanism so that its position may be laterally changed on the one hand, and may be changed in height on the other hand, and wherein said drive mechanism comprises: an oscillating drive element; coupling parts forming a connection between the drive element and the arm in order to move the respective thread guide in height; and a mechanism arranged to effect movement of one of the coupling parts to cause a lateral movement of the respective thread guide to thereby laterally change its position.
 27. Device according to claim 26, wherein the oscillating drive element comprises a motor having a motor shaft which may be rotated to and fro, in an oscillating manner.
 28. Device according to claim 27, wherein the motor is a stepping motor.
 29. Device according to claim 26, wherein the arm carrying said at least one thread guiding element is rotatable, and wherein the coupling parts comprise at least a crank that is rotatable to and fro by means of the oscillating drive element and a connecting arm provided between the crank and the arm carrying said at least one guiding element.
 30. Device according to claim 26, including means for enabling, in case of successive shed formations, by means of control of the movement of the oscillating drive element changing either or both the height and lateral position of each thread guide.
 31. Device according to claim 26, wherein said mechanism comprises a cam mechanism by which a to and fro input movement is converted to a rotational output motion.
 32. Device according to claim 31, wherein said cam mechanism comprises a cam guide on the one hand, and a cam follower working in conjunction with the cam guide on the other hand that enables generation of said rotation output motion as a result of its movement, and wherein the cam guide is provided on said connecting arm.
 33. Device according to claim 27, wherein said oscillating drive element is moveable between at least three positions, namely a first position from where the drive element may be brought into the second position in one direction and into the third position in the other direction, and in that said coupling parts and mechanism are configured such that the respective thread guide is moved in height both when the drive element is moved from the first position into the second position, as when it is moved from the first position into the third position, but in that a lateral movement of a respective thread guide only takes place in case of the movement from the first position into the third position.
 34. Device according to claim 33, wherein said cam mechanism comprises a cam guide on the one hand, and a cam follower working in conjunction with the cam guide on the other hand that enables generation of said rotation output motion as a result of its movement, and wherein the cam guide is provided on said connecting arm, and further wherein the cam guide is positioned such that the cam follower, when the drive element is moved from the first into the second position, makes contact with a cam guiding part which leaves the lateral position of the cam follower unaltered or practically unaltered, and in that the cam follower, as the drive element is moved from the first into the third position, makes contact with a cam guiding part which causes a lateral movement of the cam follower and thus brings about a lateral movement of a respective thread guide.
 35. Device according to claim 26, comprising at least one thread guiding element which is eccentrically situated in relation to a shaft onto which it is fixed, and wherein the mechanism comprises a crank-shaped part which is connected to the shaft in a fixed manner and thus forms a laterally protruding part, said crank-shaped part being connected to one of the coupling parts by a connecting rod.
 36. Device according to claim 35, wherein the arm carrying said at least one thread guiding element is rotatable, and wherein the coupling parts comprise at least a crank that is rotatable to and fro by means of the oscillating drive element and a connecting arm provided between the crank and the arm carrying said at least one guiding element, and further wherein the connecting rod is coupled to the connecting arm.
 37. Device according to claim 10, wherein the connecting rod is coupled to a respective coupling part via a first hinge point on the one hand, and in that it is connected to the crank-shaped part via a second hinge point on the other hand, wherein said hinge points comprise rotary shafts which extend mutually in different directions and which are provided at a slanting angle on the sides of the connecting arm and the crank-shaped part respectively, such that a Bennet four-bar mechanism is thereby formed.
 38. Device according to claim 26, including at least one arm carrying at least one thread guiding element for a fixed thread, said fixed thread forming a shed together with at least one leno thread.
 39. Device according to claim 26, including multiple thread guiding elements carried by respective arms, wherein each arm is formed as a lever and wherein each such lever may be coupled to another such lever.
 40. Device according to claim 26, including at least one thread guiding element provided on an arm and that is arranged to guide a fixed thread and wherein other arms and respective thread guiding elements may be moved crosswise in planes disposed next to each other.
 41. Device according to claim 26, including at least two thread guiding elements for leno threads and at least one thread guiding element for a fixed thread, wherein the thread guiding elements for the leno threads are provided on one and the same arm.
 42. Device according to claim 26, wherein fixed and leno threads extend directly backwards relative to respective thread guides and wherein at least one of the thread guides is configured as a thread guiding eye situated in a plane which extends crosswise to a plane in which the respective thread guiding element can be moved in height.
 43. Device according to claim 42, wherein at least one of the thread guiding elements includes a thread eye provided at its free end, said thread eye formed of a passage extending slantingly relative to the crosscut end of the thread guiding element, slantingly backwards, to thereby open into the side wall of the thread guiding element.
 44. Device according to claim 26, wherein a thread guiding element includes a thread eye provided at its free end that is formed of a bent wire.
 45. Device according to claim 26, wherein said coupling parts exclusively consist of parts moveable to and fro.
 46. Device according to claim 26, wherein at least one thread guiding element is provided on an arm which can rotate around a point of rotation situated in or near the central plane of a weaving surface and in that the bisector of the angle described by such a thread guiding element does not substantially deviate from the central plane.
 47. Device according to claim 46, wherein said point of rotation is situated at a distance from the central plane which is smaller than 2 cm, and in that the bisector, if it deviates from the above-mentioned central plane, forms an angle with this plane which is smaller than 15 degrees.
 48. Device for forming a selvedge on a fabric comprising different thread guiding elements, including for example at least one thread guiding element for a leno thread and at least one thread guiding element for a fixed thread, said thread guiding elements being configured as protruding elements, in particular needle-shaped elements provided with a thread guide at least on their front ends, wherein the respective threads extend mainly along either or both the longitudinal direction of the thread guiding elements and along the thread guiding elements and wherein the thread guiding elements are moveable in height by means of a drive mechanism and wherein the thread guides are formed as thread guiding eyes situated in surfaces situated crosswise to a plane in which the thread guiding element concerned can be moved in height.
 49. Device according to claim 48, wherein at least one of the thread guiding elements has a thread eye provided at its free end, formed of a passage extending slantingly relative to the crosscut end of the thread guiding element, slantingly backwards, to thereby open into the side wall of the thread guiding element.
 50. Device according to claim 49, wherein at least one of the thread guiding elements has a thread eye provided at its free end that is formed of a bent wire. 